Low air loss moisture control mattress overlay

Abstract

Disclosed are apparatus and methodology for controlling humidity (i.e., moisture) within and/or adjacent a coverlet associated with a multi-layer air mattress. Humidity sensors may be incorporated at selected locations within the coverlet and coupled to a controller that is configured to provide a closed-loop control signal to vary air flow rate through the coverlet to control the rate of moisture adjustment, such as removal. In part, present subject matter may include a combination of a Low-Air-Loss (LAL) topper, having a pair of humidity sensors, one of which is at an inlet to the LAL topper and the other of which is at a selected one of existing outlets of the LAL topper. Air flow through the LAL topper is kept constant, in accordance with its basic operation, while the two humidity sensors are part of a closed-loop feedback control system, which adjusts the humidity of the air being input at the inlet. Additionally portions of a closed-loop feedback control system may depend on the sensed rate of change of moisture, to facilitate more rapid response to changing moisture conditions. Separately, and not as part of the control feedback loop, a temperature sensor may be provided for simply indicating the temperature of the air relative to the LAL topper.

1 . An apparatus for regulating humidity of air circulating relative to a patient support, comprising:
 a mattress coverlet for association with a main patient support structure, said coverlet defining at least one air inlet thereof and at least one air outlet thereof;   a plurality of humidity sensors, coupled respectively adjacent to said mattress coverlet air inlet and said air outlet, so as to detect humidity adjacent such air inlet and air outlet, and so as to provide respective output signals indicative of each;   a coverlet air pump, coupled to said coverlet and configured to move air inside said coverlet from said air inlet thereof to said air outlet; and   a controller coupled to said coverlet air pump and said respective output signals of said humidity sensors, for controlling the humidity of the air moved inside said coverlet.   
   
   
       2 . An apparatus as in  claim 1 , wherein said controller, said coverlet air pump, and said humidity sensors are arranged so as to comprise a closed loop control system. 
   
   
       3 . An apparatus as in  claim 2 , wherein said controller is configured for adjusting operation of said coverlet air pump so as to adjust the flow rate of air moved inside said coverlet. 
   
   
       4 . An apparatus as in  claim 2 , wherein said controller is configured for adjusting the humidity of air output by said coverlet air pump so as to adjust the humidity of air moved inside said coverlet. 
   
   
       5 . An apparatus as in  claim 2 , wherein said controller is configured for determining relative humidity of air based on said humidity sensor output signals, and adjusting the humidity of air output by said coverlet air pump so as to adjust the relative humidity of air moved inside said coverlet. 
   
   
       6 . An apparatus as in  claim 2 , wherein said controller is configured for determining the rate of change of the humidity of air based on said humidity sensor output signals, and adjusting the output of said coverlet air pump so as to adjust the humidity of air moved inside said coverlet. 
   
   
       7 . An apparatus as in  claim 6 , further including an indicator associated with said controller, for indicating whenever the rate of change of the humidity exceeds predetermined levels, to indicate possible hemorrhaging or incontinence of a patient. 
   
   
       8 . An apparatus as in  claim 1 , wherein said plurality of humidity sensors include three sensors, at least one of which is adjacent said mattress coverlet air inlet. 
   
   
       9 . An apparatus as in  claim 8 , wherein there are at least two said mattress coverlet air outlets, and at least two of said plurality of humidity sensors are situated respectively adjacent such at least two mattress coverlet air outlets. 
   
   
       10 . An apparatus as in  claim 9 , wherein said controller is configured so as to average the respective outputs of said humidity sensors adjacent said at least two said mattress coverlet air outlets. 
   
   
       11 . An apparatus as in  claim 1 , wherein:
 said coverlet comprises a low air loss structure; and   said apparatus further includes a main patient support structure comprising an air flotation air mattress including its own respective air pump and associated regulator/valving structure.   
   
   
       12 . An apparatus as in  claim 1 , wherein at least one of said humidity sensors is positioned so as to be situated relatively adjacent an area for support of a patient's hips. 
   
   
       13 . An apparatus as in  claim 1 , wherein at least one of said humidity sensors may also include a temperature sensor, for sensing air temperature. 
   
   
       14 . An apparatus as in  claim 1 , wherein said mattress coverlet is associated with a multi-layer air mattress. 
   
   
       15 . An apparatus as in  claim 1 , wherein said coverlet comprises a low air loss mattress coverlet having an upper support surface defining a plurality of said air outlets. 
   
   
       16 . A system for regulating humidity of air circulating relative to a patient, comprising:
 a low air loss mattress coverlet for association with a main patient support structure, said coverlet defining at least one air inlet thereof and an upper support surface having a plurality of air outlets thereof,   a plurality of humidity sensors, coupled respectively adjacent to said mattress coverlet air inlet and said coverlet upper support surface, so as to detect humidity adjacent said air inlet and said upper support surface, and so as to provide respective output signals indicative of each;   a coverlet air pump, coupled to said coverlet and configured to move air inside said coverlet from said air inlet thereof through said air outlets thereof; and   a controller, receiving said respective output signals of said humidity sensors, and coupled to said coverlet air pump for controlling the humidity of the air moved inside said coverlet by controlling operation of said coverlet air pump.   
   
   
       17 . An apparatus as in  claim 16 , wherein said controller, said coverlet air pump, and said humidity sensors are arranged so as to comprise a closed loop control system. 
   
   
       18 . An apparatus as in  claim 17 , wherein said controller is configured for adjusting operation of said coverlet air pump so as to adjust the flow rate of air moved inside said coverlet. 
   
   
       19 . An apparatus as in  claim 17 , wherein said controller is configured for adjusting the humidity of air output by said coverlet air pump so as to adjust the humidity of air moved inside said coverlet. 
   
   
       20 . An apparatus as in  claim 17 , wherein said controller is configured for determining relative humidity of air based on said humidity sensor output signals, and adjusting the humidity of air output by said coverlet air pump so as to adjust the relative humidity of air moved inside said coverlet. 
   
   
       21 . An apparatus as in  claim 17 , wherein said controller is configured for determining the rate of change of the humidity of air based on said humidity sensor output signals, and adjusting the output of said coverlet air pump so as to adjust the humidity of air moved inside said coverlet. 
   
   
       22 . An apparatus as in  claim 21 , further including an indicator associated with said controller, for indicating whenever the rate of change of the humidity exceeds predetermined levels, to indicate possible hemorrhaging or incontinence of a patient. 
   
   
       23 . An apparatus as in  claim 16 , wherein said plurality of humidity sensors include three sensors, at least one of which is adjacent said mattress coverlet air inlet. 
   
   
       24 . An apparatus as in  claim 23 , wherein there are at least two said mattress coverlet air outlets, and at least two of said plurality of humidity sensors are situated respectively adjacent said coverlet upper support surface. 
   
   
       25 . An apparatus as in  claim 24 , wherein said controller is configured so as to average the respective outputs of said humidity sensors adjacent said coverlet upper support surface. 
   
   
       26 . An apparatus as in  claim 16 , wherein said apparatus further includes a main patient support structure comprising an air flotation air mattress including its own respective air pump and associated regulator/valving structure. 
   
   
       27 . An apparatus as in  claim 16 , wherein at least one of said humidity sensors is positioned so as to be situated relatively adjacent an area for support of a patient's hips. 
   
   
       28 . A system of closed loop control for regulating humidity of air circulating relative to a patient support, comprising:
 an air flotation air mattress with a plurality of air bladders;   an air flotation mattress air pump;   air flotation mattress regulator and valving means, for receiving air flow from said air flotation mattress air pump and for regulating inflation of said air bladders of said air flotation air mattress;   a low air loss mattress coverlet received on said air flotation air mattress, said coverlet defining at least one air inlet thereof and an upper support surface having a plurality of air outlets thereof;   a plurality of humidity sensors, coupled respectively adjacent to said mattress coverlet air inlet and said coverlet upper support surface, so as to detect humidity adjacent said air inlet and said upper support surface, and so as to provide respective output signals indicative of each;   a coverlet air pump, coupled to said coverlet and configured to move air inside said coverlet from said air inlet thereof through said air outlets thereof; and   a controller, receiving said respective output signals of said humidity sensors, and coupled to said coverlet air pump, for controlling the humidity of the air moved inside said coverlet by controlling operation of said coverlet air pump.   
   
   
       29 . An apparatus as in  claim 28 , wherein said controller, said coverlet air pump, and said humidity sensors are arranged so as to comprise a closed loop control system. 
   
   
       30 . An apparatus as in  claim 29 , wherein said controller is configured for adjusting operation of said coverlet air pump so as to adjust the flow rate of air moved inside said coverlet. 
   
   
       31 . An apparatus as in  claim 29 , wherein said controller is configured for adjusting the humidity of air output by said coverlet air pump so as to adjust the humidity of air moved inside said coverlet. 
   
   
       32 . An apparatus as in  claim 29 , wherein said controller is configured for determining relative humidity of air based on said humidity sensor output signals, and adjusting the humidity of air output by said coverlet air pump so as to adjust the relative humidity of air moved inside said coverlet. 
   
   
       33 . An apparatus as in  claim 29 , wherein:
 said controller is configured for determining the rate of change of the humidity of air based on said humidity sensor output signals, and adjusting the output of said coverlet air pump so as to adjust the humidity of air moved inside said coverlet; and   wherein said apparatus further includes an indicator associated with said controller, for indicating whenever the rate of change of the humidity exceeds predetermined levels, to indicate possible hemorrhaging or incontinence of a patient.   
   
   
       34 . An apparatus as in  claim 28 , wherein said plurality of humidity sensors include three sensors, with one of said humidity sensors located adjacent said mattress coverlet air inlet, and with two of said humidity sensors located adjacent said coverlet upper support surface, at least one of which is positioned so as to be situated relatively adjacent an area for support of a patient's hips. 
   
   
       35 . An apparatus as in  claim 34 , wherein said controller is configured so as to average the respective outputs of said humidity sensors adjacent said coverlet upper support surface. 
   
   
       36 . Methodology for regulating humidity of air circulating relative to a patient support, comprising:
 providing a mattress coverlet for association with a main patient support structure, such coverlet defining at least one air inlet thereof and at least one air outlet thereof;   providing a plurality of humidity sensors, coupled respectively adjacent to such mattress coverlet air inlet and such air outlet, so as to detect humidity adjacent such air inlet and air outlet, and so as to provide respective output signals indicative of each;   providing a coverlet air pump, coupled to such coverlet and configured to move air inside such coverlet from such air inlet thereof to such air outlet; and   providing a controller coupled to such coverlet air pump and such respective output signals of the humidity sensors, for controlling the humidity of the air moved inside such coverlet.   
   
   
       37 . Methodology as in  claim 36 , wherein such controller, coverlet air pump, and humidity sensors are arranged so as to comprise a closed loop control system, with such controller configured for adjusting at least one of operation of said coverlet air pump so as to adjust the flow rate of air moved inside said coverlet, and for adjusting the humidity of air output by said coverlet air pump so as to adjust the humidity of air moved inside said coverlet. 
   
   
       38 . Methodology as in  claim 37 , wherein such controller is configured for determining relative humidity of air based on such humidity sensor output signals, and adjusting the humidity of air output by such coverlet air pump so as to adjust the relative humidity of air moved inside such coverlet. 
   
   
       39 . Methodology as in  claim 37 , wherein such controller is configured for determining the rate of change of the humidity of air based on such humidity sensor output signals, for adjusting the output of such coverlet air pump so as to adjust the humidity of air moved inside such coverlet, and for indicating whenever the rate of change of the humidity exceeds predetermined levels, to indicate possible hemorrhaging or incontinence of a patient. 
   
   
       40 . Methodology as in  claim 36 , further including:
 providing such coverlet as a low air loss mattress coverlet having an upper support surface defining a plurality of such air outlets;   providing three humidity sensors, with one of such sensors adjacent such mattress coverlet air inlet, and with two of such sensors adjacent such coverlet upper support surface.   
   
   
       41 . Methodology as in  claim 40 , further including averaging the respective outputs of such two humidity sensors adjacent such coverlet upper support surface. 
   
   
       42 . Methodology as in  claim 36 , further including providing a main patient support structure for support of such coverlet, and comprising an air flotation air mattress including its own respective air pump and associated regulator/valving structure. 
   
   
       43 . Methodology as in  claim 36 , further including situating at least one of such humidity sensors relatively adjacent an area for support of a patient's hips. 
   
   
       44 . Methodology as in  claim 36 , further including sensing air temperature of the air being circulated relative to a patient support.